Method for Manufacturing a Security Paper and Microlens Thread

ABSTRACT

A method for manufacturing a security paper includes an endless microlens thread having a top and an opposing bottom with the top provided at least in fractional regions with microlenses. A paper web having a predetermined ridge pattern is produced and defines ridge regions in which the microlens is embedded in the interior of the paper, and that exhibits, lying between the ridge regions, window regions in which the microlens thread emerges at the surface of the paper web. The microlens thread is introduced into the paper web and, at the same time, is joined on its bottom and, in the ridge regions, also on its top with the paper web. The paper web with the microlens thread forms the security paper.

The present invention relates to a method for manufacturing a securitypaper, as well as a microlens thread for introduction into a paper webwith such a method.

For protection, value documents, such as banknotes, stocks, bonds,certificates, vouchers, checks, valuable admission tickets and otherpapers that are at risk of counterfeiting, such as passports or otheridentification documents, are often provided with security elements thatpermit the authenticity of the value document to be verified, and thatsimultaneously serve as protection against unauthorized reproduction.The security elements can be developed, for example, in the form of asecurity thread that is completely or partially embedded in a banknote.

In recent years, security threads having microlenses have come into useon the banknote market. These microlens threads differ significantlyfrom metalized threads and offer attractive optical properties. Themicrolens threads are furnished, on the side facing the viewer, withmicrolenses whose focusing effect is created by light refraction on anapproximately spherically curved surface. In the focal plane of themicrolenses, micropatterns are located that are arranged such that,through the coaction of the microlenses and the micropatterns, it ispossible to depict for the viewer a magnified image having specialmotion effects.

In order not to impair the focusing effect of the microlenses and thusthe optical effect of the microlens thread, the lens side of the threadis not provided with adhesive before the embedding in a paper web, as isthe case in conventional security threads, such as hologram threads.However, the dispensation with adhesive on the top of the thread (lensside) often leads to a reduced stability of the banknotes produced, andin some cases even to a wrinkling on the banknote back.

Proceeding from this, the object of the present invention is to avoidthe disadvantages of the background art and especially to specify amethod for manufacturing a security paper that facilitates a secureembedding of a microlens thread in the paper, and that simultaneouslyensures, in the window regions in which the microlens thread emerges atthe surface of the paper, an attractive visual appearance of themicrolens thread.

This object is solved by the features of the independent claims.Developments of the present invention are the subject of the dependentclaims.

According to the present invention, in a generic method, it is providedthat

-   -   M) an endless microlens thread is provided that exhibits a top        and an opposing bottom, the top being provided, at least in        fractional regions, with microlenses,    -   P) a paper web is produced having a predetermined ridge pattern        that exhibits ridge regions in which the microlens thread is        embedded in the interior of the paper web, and that exhibits,        lying between the ridge regions, window regions in which the        microlens thread emerges at the surface of the paper web, and    -   E) the microlens thread is introduced into the paper web and, at        the same time, is joined on its bottom and, in the ridge        regions, also on its top, with the paper web, the paper web with        the introduced microlens thread forming the security paper.

In a preferred method variant, it is provided that

-   -   before the introduction into the paper web, the microlens thread        is provided on its top with an adhesive layer in the form of the        ridge pattern and    -   in step E), the microlens thread is introduced into the paper        web in register, such that the adhesive-coated regions of the        microlens thread coincide with the ridge regions of the paper        web.

A registered introduction of the microlens thread can especially occuraccording to one of the methods described in document WO 2004/050991 A1.In this respect the disclosure of this document is incorporated in thepresent application by reference.

In some designs, the microlens thread can include a motif having a motifjump. As described in greater detail in document WO 2008/145333 A2, inmanufacturing a microlens thread, normally an endless security elementfoil is first manufactured as roll material, wherein, when conventionalmanufacturing methods are used, breaking points always occur, especiallygaps or a misalignment in the appearance of the security elements. Thesebreaking points come from the fact that the pre-products for theembossing dies used in manufacturing are generally manufactured as flatplates that are fitted on an impression or embossing cylinder. The imagepatterns that adjoin on both sides do not, as a general rule, match atthe junctions and, after printing or embossing, lead, in the appearanceof the finished security elements, to a motif jump of the kind cited.According to an advantageous embodiment of the present invention, amicrolens thread that includes a motif having a motif jump is introducedinto the paper web in register, such that the motif jump comes to lie inone of the ridge regions of the paper web. The motif jump then remainshidden from the viewer.

Motif jumps potentially also occur multiple times within an embossingcylinder. For example, in the event that the patterns are composed fromsmall segments by means of recombination, seams having motif jumpsresult. In general, due to the method, motif jumps are created both inthe grid of the micropatterns and in the grid of the microlenses. Here,it is usually attempted to bring the two seams into overlap atmanufacture, such that the impression of only one motif jump is createdfor the viewer.

In a modification of the described method, immediately before enteringinto the paper web, the microlens thread is selectively printed on withan adhesive layer in those regions of its top that, at sheet formation,come to lie below ridge regions of the paper web.

In a further preferred method variant, it is provided that

-   -   before the introduction into the paper web, the microlens thread        is provided in an opening region with a plurality of openings in        the form of the ridge pattern, and    -   in step E), the microlens thread is introduced into the paper        web in register, such that the regions of the microlens thread        that are provided with openings coincide with the ridge regions        of the paper web.

Also in this variant, the microlens thread can include a motif having amotif jump, and the microlens thread be introduced in register, suchthat the motif jump comes to lie in one of the ridge regions of thepaper web and is thus hidden for the viewer.

According to a modification of the method, immediately before enteringinto the paper web, the microlens thread is selectively provided withopenings in those regions of its top that, at sheet formation, come tolie below ridge regions of the paper web.

The openings are advantageously produced by punching or laser cutting.If the openings are produced only immediately before the entry of themicrolens thread into the paper web, then they are preferably producedby laser cutting.

In all designs, the paper web is expediently formed having thepredetermined ridge pattern in a paper machine, and the endlessmicrolens thread enters into the paper machine.

According to a further preferred method variant, it is provided that, instep M), a microlens thread is provided whose top exhibits fractionalregions having microlenses and microlens-free fractional regions, themicrolens-free fractional regions being smaller than the width of theridge regions of the ridge pattern in the paper web, and themicrolens-free fractional regions being coated with adhesive before theintroduction into the paper web. The microlens thread is especiallyintroduced into the paper web not in register such that, in every windowregion, microlenses can be seen at least in some regions, and a portionof the adhesive-coated fractional regions always come to lie below ridgeregions of the paper web.

According to a further preferred method variant, it is provided that, instep M), a microlens thread is provided that, on the one hand, exhibitsfractional regions having microlenses, which fractional regions arecoated with adhesive before the introduction into the paper web, andwhich are smaller than the width of the ridge regions of the ridgepattern in the paper web, and on the other hand, exhibits fractionalregions having microlenses that are not coated with adhesive before theintroduction into the paper web. The microlens thread is especiallyintroduced into the paper web not in register, such that, in everywindow region, microlenses that exhibit no adhesive coating can be seenat least in some regions, and a portion of the adhesive-coatedfractional regions always come to lie below ridge regions of the paperweb.

In all described method variants, the microlens thread is advantageouslycontiguously provided on its bottom with an adhesive layer before theintroduction into the paper web.

The present invention also includes a microlens thread for introductioninto a paper web, especially with the method just described. Themicrolens thread includes a top and an opposing bottom, the topexhibiting fractional regions having microlenses, and exhibitingmicrolens-free fractional regions that are coated with adhesive.

The fractional regions having microlenses and the microlens-freefractional regions advantageously form, on the top of the thread,alternating strips that each completely occupy the width of themicrolens thread, and that each exhibit, in the longitudinal directionof the microlens thread, a dimension between 1 mm and 30 mm, preferablybetween 3 mm and 12 mm.

The fractional regions having microlenses and the microlens-freefractional regions can usually be present in the form of rectangles.However, it would also be possible for the fractional regions havingmicrolenses and the microlens-free fractional regions to be present inthe form of diagonals. Especially in wider threads, it is possible toproduce diagonal paper ridges.

The bottom of the microlens thread is preferably contiguously coatedwith adhesive.

Further exemplary embodiments and advantages of the present inventionare explained below by reference to the drawings, in which a depictionto scale and proportion was dispensed with in order to improve theirclarity.

Shown are:

FIG. 1 a schematic diagram of a banknote having an embedded microlensthread, manufactured according to the present invention,

FIG. 2 schematically, the layer structure of a microlens thread beforethe embedding in the security paper,

FIG. 3 a cross-section of a security paper having an embedded microlensthread according to FIG. 2,

FIG. 4 a top view of the microlens thread in FIG. 2,

FIG. 5 a top view of a further microlens thread before the embedding ina security paper,

FIG. 6 a cross-section of the microlens thread in FIG. 5,

FIG. 7 a cross-section of a security paper having an embedded microlensthread according to FIGS. 5 and 6,

FIG. 8 a cross-section of the microlens thread according to the presentinvention; and

FIG. 9 a cross-section of a security paper having an embedded microlensthread according to FIG. 8.

The invention will now be explained using a banknote as an example. Forthis, FIG. 1 shows a schematic diagram of a banknote 10 manufacturedaccording to the present invention, having a microoptical windowsecurity thread 12 that, in the following, is also referred to asmicrolens thread for short. The microlens thread 12 emerges at thesurface of the banknote 10 in window regions 14, while it is embedded inthe interior of the banknote 10 in the ridge regions 16 lyingtherebetween.

In a first exemplary embodiment of the present invention, the microlensthread 12 illustrated in FIGS. 2 and 4 is used for the manufacture of asecurity paper. FIG. 3 shows a cross-section of the security paper 50with the already embedded microlens thread 12. Here, at the manufactureof security paper, the microlens thread enters, for example in endlessform, into a paper machine and is embedded there in a paper web formingon a cylinder mold. The paper web together with the embedded microlensthread is referred to in this description as security paper. From such asecurity paper is created, after further processing steps and separationof the ups of a paper web or a paper sheet, a banknote 10 as shown inFIG. 1.

FIG. 2 shows, schematically, the layer structure of the microlens thread12 before the embedding in the security paper, with only those portionsof the layer structure that are required to explain the functionalprinciple being depicted. FIG. 4 shows a top view of the microlensthread 12 in FIG. 2.

The microlens thread 12 includes a support 20 in the form of atransparent plastic foil, for example a PET foil about 20 μm thick. Thetop 30 of the microlens thread 12 exhibits a grid-shaped arrangement ofmicrolenses 22 that form, on the surface of the support foil, a latticehaving a prechosen symmetry. The spherically or aspherically designedmicrolenses 22 preferably exhibit a diameter between 5 μm and 50 μm, andespecially a diameter between merely 10 μm and 35 μm, and are thus notperceptible with the naked eye. It is understood that, in other designs,also larger or smaller dimensions may be considered. Also the use ofcylindrical lenses is similarly possible.

On the bottom 32 of the microlens thread 12 is arranged a motif layer 26that includes a likewise grid-shaped arrangement of micromotif elements28. Also the arrangement of the micromotif elements 28 forms a latticehaving a prechosen symmetry, with a desired magnification effect,characteristic motion effects and/or tilt effects being produced due tothe coordination of the lattice of the microlenses 22 and thearrangement of the micromotif elements 28. The micromotif elements arenot perceptible with the naked eye. Now, reference is additionally madeto WO 2009/000528 A1, in which it is explained that the micropatternscan also consist of image fragments that are not arranged repeatingly.The microlens thread 12 typically includes further layers 24, such asprotective, cover or further functional layers, which, however, are notsignificant for the present invention and are thus not described ingreater detail.

Due to the manufacture with embossing cylinders, the motif perceived bythe viewer will usually exhibit a motif jump, as described in greaterdetail in document WO 2008/145333 A2.

Now, to manufacture a security paper, a paper web 50 having apredetermined ridge pattern 18 (FIG. 1) is produced on the cylinder moldof a paper machine. The ridge pattern 18 exhibits ridge regions 16 inwhich the microlens thread 12 is later embedded in the interior of thefinished paper web 50. Between the ridge regions 16 lie window regions14 in which the microlens thread 12 emerges at the surface of thefinished paper web 50.

As schematically depicted in FIGS. 2 and 4, before the introduction intothe paper web 50, the microlens thread 12 is provided on its top 30 withan adhesive layer 40 in the form of the ridge pattern 18, such that theadhesive layer 40 forms an adhesive pattern 48 whose sequence ofuncoated regions 44 and coated regions 46 corresponds to the sequence ofthe window regions 14 and ridge regions 16 of the ridge pattern 18. Thebottom 32 of the microlens thread 12 is provided with a contiguousadhesive layer 42.

Said microlens thread 12 coated in this way with adhesive 40, 42 is nowintroduced in register into the paper web 50, such that theadhesive-coated regions 46 of the microlens thread coincide with theridge regions 16 of the paper web 50, as shown in FIG. 3.

Such an introduction in register can especially occur according to oneof the methods described in document WO 2004/050991 A1. For example, themicrolens thread 12 can be introduced into the paper web by means of abiased coil. A first sensor detects the position of the coated regions46 shortly before the introduction into the paper web, a second sensorthe position of the ridges 16 formed in the paper web immediately aftersheet formation. The positions detected by the two sensors are analyzedand used to control the magnitude of the bias. When the bias isincreased, the microlens thread 12 is stretched more strongly, and whenthe bias is lowered, the stretching is reduced. In this way, themicrolens thread 12, with its coated and uncoated regions 44, 46, can bealigned in perfect register with the window and ridge regions 14, 16.

For the registered thread embedding, the procedure is preferably suchthat the thread bears a register mark that is recognized particularlywell by a detection system. The thread embedding is then controlled atthe thread by means of tensile stress in such a way that the registermark of the thread has a fixed local reference to the register mark ofthe paper, usually a watermark. Here, the regions in which the threadexhibits adhesive on the top then have a fixed, known local reference tothe register mark of the thread. Similarly, the ridge regions in thepaper have a fixed local relationship to the register mark in the paper.

Through said approach it is ensured that the ridge regions 16 of thepaper web 50 are glued to the microlens thread 12, such that a secureembedding of the microlens thread 12, without wrinkling and withoutlifting up or tearing out the paper ridges at manufacture, is ensured.Likewise, stability of the paper ridges to circulation stresses issignificantly improved. At the same time, the microlenses 22 of theuncoated regions 44 that are visible in the window regions 14 remainfree of adhesive, such that the optical properties of the microlenses 22are not impaired. The microlens thread 12 thus displays, after itsembedding in the paper web 50, the desired clear visual appearance inthe window regions 14.

In advantageous embodiments, the uncoated regions 44 and the coatedregions 46 exhibit the same size as the window regions 14 and the ridgeregions 16, respectively. In some embodiments, it is also provided thatthe coated regions 46 are smaller, for example no more than 10% or nomore than 50% smaller, than the ridge regions 16. How much shorter theglue-coated portion should be compared with the paper ridges of thethread also depends strongly on the register tolerance when embeddingthe thread in register. With, for example, ±1 mm register tolerance whenintroducing the thread in register, the glue-free regions of the threadshould be 2 mm shorter than the paper ridges. Even if, in each case,only a portion of the microlens thread 12 is glued to the ridge regions16, a significantly improved embedding results compared with thebackground art.

Also designs in which the uncoated regions 44 are somewhat smaller thanthe window regions 14 may be considered. However, the focusing effect ofadhesive-coated microlenses 22 in the window regions 14 is reduced orcanceled, such that the uncoated regions 44 are preferably not more than10%, particularly preferably not more than 5% smaller than the windowregions 14.

A further advantage of the introduction of the microlens thread 12 inregister consists in that any motif jumps 34 in the motif image can behidden under a paper ridge 16 of the security paper 50, as shown in FIG.3. In this way, the uniformity of the visual appearance of the microlensthread 12 is further increased.

In a modification of the described method sequence, the microlens thread12 is not introduced into the paper web 50 in register, but rather is,immediately before the entry into the paper machine, printed on with anadhesive pattern 48 in such a way that the coated regions 46 come to liein the depressed sections of the cylinder mold, in which the paperridges 16 form. For this, a sensor, for example, can detect the positionof the ridges 16 formed in the paper web at sheet formation, and thedetected position can be used to control the printing positions for theadhesive pattern 48. Also in this way, the uncoated and coated regions44, 46 can be aligned in perfect register with the window and ridgeregions 14, 16.

A further variant of the present invention will now be explained withreference to FIGS. 5 to 7. Here, FIGS. 5 and 6 show a top view and across-section, respectively, of the microlens thread 60 before theembedding in the security paper, and FIG. 7 shows a cross-section of thesecurity paper 50 having the embedded microlens thread 60.

In the variant in FIGS. 5 to 7, the microlens thread 60 is not coated onits top 30 with adhesive, but rather, before the introduction into thepaper web 50, it is provided with an opening pattern 68 in the form ofthe ridge pattern 18. The opening pattern 68 consists of a sequence ofregions 66, having openings 62 and regions 64 without openings, thatcorresponds to the sequence of the ridge regions 16 and window regions14 of the ridge pattern 18. The bottom 32 of the microlens thread 60 ispreferably provided with a contiguous adhesive layer 42.

The microlens thread 60 is now introduced into the paper web 50 inregister, such that the regions 66 of the microlens thread 60 that areprovided with openings coincide with the ridge regions 16 of the paperweb 50, as already described in principle in connection with FIGS. 2 to4. In this case, the first sensor detects the position of the openings62 shortly before the introduction of the microlens thread 12 into thepaper web. In this way, the microlens thread 60 with its opening pattern68 can be aligned in perfect register with the window and ridge regions14, 16.

In this variant of the present invention, due to the provision of theopenings 62, it is achieved that, at paper formation, under the ridgeregions 16, paper fibers or other components of the substrate 50 canpenetrate through the openings 62 to create a connection between theridge regions 16 and the substrate material 52 under the microlensthread 60 (FIG. 7). In this way, also a close connection between thepaper web 50 and the microlens thread 60 is achieved, and thus a secureembedding without wrinkling Since the top 30 of the microlens thread 60remains adhesive-free, the optical properties of the microlenses 22 arenot impaired.

The openings 62 can, for example, be punched or produced through lasercutting. Every region 66 can include one or also multiple openings 62.For illustration, FIGS. 6 and 7 show a design having, in each case, onlyone opening 62 per region 66, while FIG. 5 illustrates a design havingthree openings 62 per region 66.

In a modification of the described method sequence, the microlens thread60 is not introduced into the paper web 50 in register, but rather, itis provided only immediately before the entry into the paper machine,through laser impingement, with the opening pattern 68, in such a waythat the regions 66 having openings 62 come to lie in the depressedsections of the cylinder mold, in which the paper ridges 16 form. Forthis, for example, a sensor can detect the position of the ridges 16formed in the paper web, and the detected position can be used tocontrol the laser beam. Also in this way, the opening pattern 68 can bealigned in perfect register with the window and ridge regions 14, 16.

In a further variant of the present invention that is illustrated inFIGS. 8 and 9, a microlens thread 70 is used that exhibits, on its top30, a sequence of fractional regions 74 having microlenses 22 andmicrolens-free fractional regions 76. The motif layer and any furtherlayers of the microlens thread 70 are, for the sake of clarity, notshown in FIGS. 8 and 9. The microlens-free fractional regions 76 of thetop 30 are coated with adhesive 40, and also the bottom of the microlensthread 70 is contiguously coated with adhesive 42.

Here, the adhesive-coated, microlens-free fractional regions 76 aredeveloped to be smaller than the width of the window regions 14 of theridge pattern 18. In this way, it is ensured that, when the microlensthread 70 is not introduced into a security paper 50 in register,microlenses 22 can be seen in every window region 14, at least in someregions (FIG. 9).

In this way, on the one hand, a visually attractive appearance isobtained, and on the other hand, an embedding that is improved over thebackground art can be achieved also without an introduction of themicrolens thread 70 in register, since a portion of the adhesive-coatedfractional regions 76 will always come to lie below ridge regions 16 ofthe paper web, as illustrated in FIG. 9.

According to a modification of the above-mentioned variant of thepresent invention illustrated in FIGS. 8 and 9, the adhesive-coatedregions can definitely also exhibit microlenses. Indeed, saidmicrolenses would become optically ineffective due to the adhesivecoating, but they permit a uniform design of the thread withmicrolenses.

According to a further modification of the above-mentioned variant ofthe present invention illustrated in FIGS. 8 and 9, especially in widerthreads, it is appropriate to arrange the microlens-free regionsdiagonally or in strip form alongside the thread and thus, ifapplicable, to provide, across the entire length of the thread, regionsthat can be coated with glue.

The adhesive or glue used in the present invention can be, for example,a heat seal coating. Furthermore, the adhesive can exhibit securityfeatures, for example dyes or color pigments and luminescent substances.

LIST OF REFERENCE SIGNS

-   10 Banknote-   12 Microlens thread-   14 Window regions-   16 Ridge regions-   18 Ridge pattern-   20 Support-   22 Microlenses-   24 Further layers-   26 Motif layer-   28 Micromotif elements-   30 Top-   32 Bottom-   34 Motif jump-   40 Adhesive layer top-   42 Adhesive layer bottom-   44 Uncoated regions-   46 Coated regions-   48 Adhesive pattern-   50 Paper web-   52 Substrate material-   60 Microlens thread-   62 Openings-   64 Regions without openings-   66 Regions with openings-   68 Opening pattern-   70 Microlens thread-   74 Fractional regions with microlenses-   76 Microlens-free fractional regions

1-16. (canceled)
 17. A method for manufacturing a security paper,comprising: (A) providing an endless microlens thread defining a top andan opposing bottom, the top being provided with microlenses at least infractional regions; (B) producing a paper web having a predeterminedridge pattern defining ridge regions in which the microlens thread isembedded in the interior of the paper web, and that exhibits, lyingbetween the ridge regions, window regions in which the microlens threademerges at the surface of the paper web; and (C) introducing themicrolens thread into the paper web and, at the same time, joining onits bottom and, in the ridge regions, also on its top, with the paperweb, the paper web with the introduced microlens thread forming thesecurity paper.
 18. The method according to claim 17, wherein before theintroduction into the paper web, the microlens thread is provided on itstop with an adhesive layer in the form of the ridge pattern; and whereinin step C), the microlens thread is introduced into the paper web inregister, such that the adhesive-coated regions of the microlens threadcoincide with the ridge regions of the paper web.
 19. The methodaccording to claim 18, wherein the microlens thread includes a motifhaving a motif jump, the microlens thread being introduced in register,such that the motif jump comes to lie in one of the ridge regions of thepaper web.
 20. The method according to claim 17, wherein the adhesivelayer forms an adhesive pattern having a sequence of uncoated regionsand adhesive-coated regions, the adhesive-coated regions each having anup to 50% smaller dimension than the ridge regions of the paper web. 21.The method according to claim 17, wherein, immediately before enteringinto the paper web, the microlens thread is selectively coated withadhesive in those regions of its top that, at sheet formation, come tolie below ridge regions of the paper web.
 22. The method according toclaim 17, wherein before the introduction into the paper web, themicrolens thread is provided in an opening region with a plurality ofopenings in the form of the ridge pattern; and wherein in step C), themicrolens thread is introduced into the paper web in register, such thatthe regions of the microlens thread that are provided with openingscoincide with the ridge regions of the paper web.
 23. The methodaccording to claim 22, wherein the microlens thread includes a motifhaving a motif jump, the microlens thread being introduced in register,such that the motif jump comes to lie in one of the ridge regions of thepaper web.
 24. The method according to claim 17, wherein, immediatelybefore entering into the paper web, the microlens thread is selectivelyprovided with openings in those regions of its top that, at sheetformation, come to lie below ridge regions of the paper web.
 25. Themethod according to claim 22, wherein the openings are produced bypunching or laser cutting.
 26. The method according to claim 17, whereinthe paper web having the predetermined ridge pattern is formed in apaper machine, and the endless microlens thread enters into the papermachine.
 27. The method according to claim 17, wherein, in step A), amicrolens thread is provided whose surface exhibits fractional regionshaving microlenses, said fractional regions are coated with adhesivebefore introduction into the paper web, and are smaller than the widthof the ridge regions of the ridge pattern in the paper web.
 28. Themethod according to claim 17, wherein, in step A), a microlens thread isprovided whose surface exhibits fractional regions having microlensesthat are not coated with adhesive before the introduction into the paperweb
 29. The method according to claim 17, wherein, in step A), amicrolens thread is provided whose top exhibits fractional regionshaving microlenses and microlens-free fractional regions, themicrolens-free fractional regions being smaller than the width of theridge regions of the ridge pattern in the paper web, and themicrolens-free fractional regions being coated with adhesive before theintroduction into the paper web.
 30. The method according to claim 17,wherein the microlens thread is provided contiguously on its bottom withan adhesive layer before the introduction into the paper web.
 31. Amicrolens thread for introduction into a paper web, according to themethod of claim 29, having a top and an opposing bottom, wherein the topexhibits fractional regions having microlenses, and exhibitsmicrolens-free fractional regions that are coated with adhesive.
 32. Themicrolens thread according to claim 31, wherein the fractional regionshaving microlenses and the microlens-free fractional regions on the topform alternating strips that each completely occupy the width of themicrolens thread and that each exhibit, in the longitudinal direction ofthe microlens thread, a dimension between 1 mm and 30 mm.
 33. Themicrolens thread according to claim 31, wherein the bottom of themicrolens thread is coated contiguously with adhesive.